Gallons to Liters
Type a value in either box to convert between gallons and liters. The factor is 3.78541.
| Gallons | Liters |
|---|---|
| 1 gal | 3.785412 L |
| 2 gal | 7.570824 L |
| 3 gal | 11.356235 L |
| 5 gal | 18.927059 L |
| 10 gal | 37.854118 L |
| 25 gal | 94.635295 L |
| 50 gal | 189.270589 L |
| 100 gal | 378.541178 L |
How to use
- Enter a value in the Gallons field.
- The Liters figure appears immediately — no button to press.
- Typing in the Liters field converts back to Gallons the same way.
- Use the reference table for the values that come up most often.
Gallons to Liters formula
Converting gallons to liters is a single multiplication by 3.78541178.
L = gal × 3.78541178
Why this factor: the gallon and the liter are both defined against the liter, so dividing one definition by the other gives 3.78541178 directly. Both definitions are set out in full below.
To go the other way, divide by 3.78541178 — or use the Liters to Gallons converter, which is the same calculation reversed.
Worked example
Take 8 gal and multiply by the factor 3.78541178: the result is 30.283294 L.
8 gal × 3.78541178 = 30.283294 L
The converter above does this for any value you type, in either direction.
What is a gallon?
A US liquid gallon is the standard large-volume unit in the United States.
Definition: Defined as exactly 231 cubic inches, which works out to exactly 3.785411784 liters.
Where it is used: Fuel sales, milk and beverage containers, and paint in the US.
Worth knowing: The imperial gallon used in the UK and Canada is about 20% larger, at 4.54609 L — so 'miles per gallon' figures are not comparable between the two.
What is a liter?
A liter is the everyday metric unit of volume, equal to the space in a 10 cm cube.
Definition: Exactly one cubic decimeter, so exactly 0.001 cubic meter. Accepted for use with SI but not an SI unit itself.
Where it is used: Fuel, beverages, engine displacement, and recipe volumes across the metric world.
Gallons vs Liters
The gallon is a US customary unit while the liter is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many liters are in a gallon?
One gallon equals 3.78541178 liters.
What is the formula to convert gallons to liters?
Multiply the number of gallons by 3.78541178. To reverse it, divide by 3.78541178 instead.
How do I convert liters back to gallons?
Divide by 3.78541178, which is the same as multiplying by 0.264172052.
How many liters are in 10 gallons?
10 gal works out to 37.854118 L.
Is there anything to watch out for with gallons?
The imperial gallon used in the UK and Canada is about 20% larger, at 4.54609 L — so 'miles per gallon' figures are not comparable between the two.
How is the gallon defined?
Defined as exactly 231 cubic inches, which works out to exactly 3.785411784 liters.